How Dinosaurs went extinct?

Dinosaur as we all know were one of the most successful animals to ever rule the planet. For almost 150 million years their do...

Dinosaur as we all know were one of the most successful animals to ever rule the planet.

For almost 150 million years their dominance was unchallenged except by other dinosaurs. Then all of a sudden they disappeared, something must have killed them off.

Scientists have investigated a sharp layer of rock in mines all across the world formed about 65 million years ago which they called K-T line.

Below this line, there were a lot of dinosaur fossils while above it, there was none which made scientists suspicious about any catastrophic event.

It was until 1979 when Walter Alvarez came up with his dinosaur extinction theory. He found a rich amount of iridium inside the K-T line which is very less abundant on Earth and generally found in asteroids.

Iridium found in K-T line is almost 10,000 times more than ordinary soil which he suggested must had come from space. And after some further calculations, it was found that he was right and the asteroid must be 10km in radius which crashed near the gulf of Mexico(known as chicxulub crater) about 65 million years ago creating a fireball which was equivalent to almost 10 billion Hiroshima bombs.The crater is still visible through certain mapping machines.

As soon as the asteroid smashed, the shockwave generated would have destroyed all life for hundreds of miles around, followed by a mile high tsunami and poisonous gases. Hot gases made earth's temperature more than 200°C. The cloud of dust and smoke blocked all the sunlight for several years killing all the plants and eventually the remaining dinosaur over the world. Due to the lack to sunlight, temperature too went down to the freezing point. All these events led to the mass extinction of more than 75% of the living species of that time which is too horrible to imagine.

Only some small mammals , some birds and crocodile survied the crash. 

It is quite interesting to know that dinosaurs ruled earth for almost 150 million years and we are here since just 5-7 million years.

We should consider ourselves lucky that such Catastrophy didn't occurred in the near human history, else neither would you be there reading this article nor me to write this. We are too small and tiny in front of this universe and we can just hope that we do not encounter with these horrible events until we make ourselves capable of handling such.